The present invention relates to a process for preparing aminobenzoic acid or an aminobenzoic acid conversion product, comprising the steps of: (I) providing an aqueous solution of aminobenzoic acid using a fermentation process; (II) adsorbing aminobenzoic acid; (III) desorbing aminobenzoic acid at a pH in the range from −0.8 to 3.0, preferably −0.5 to 3.0, more preferably 0.1 to 3.0, very preferably 0.5 to 2.5, very exceptionally preferably 1.0 to 2.0; (IV) obtaining the aminobenzoic acid from the desorbate obtained in step (III); (V) optionally further converting the aminobenzoic acid obtained in step (IV) to an aminobenzoic acid conversion product.

The present invention relates to a process for preparing aminobenzoic acid or an aminobenzoic acid conversion product, comprising the steps of: (I) providing an aqueous solution of aminobenzoic acid using a fermentation process; (II) adsorbing aminobenzoic acid; (III) desorbing aminobenzoic acid at a pH in the range from −0.8 to 3.0, preferably −0.5 to 3.0, more preferably 0.1 to 3.0, very preferably 0.5 to 2.5, very exceptionally preferably 1.0 to 2.0; (IV) obtaining the aminobenzoic acid from the desorbate obtained in step (III); (V) optionally further converting the aminobenzoic acid obtained in step (IV) to an aminobenzoic acid conversion product.

A method for purifying an amino acid from an initial mixture is disclosed, in which the amino acid includes an aromatic ring and has an acidity constant Ka, the method including: a first step of putting the initial mixture into contact with a strong cation resin, at a pH greater than or equal to pKa; and a second elution step with an aqueous solution of eluent having a pH greater than the pH of the first step, giving the possibility of collecting a flow enriched in the amino acid.

A method for purifying an amino acid from an initial mixture is disclosed, in which the amino acid includes an aromatic ring and has an acidity constant Ka, the method including: a first step of putting the initial mixture into contact with a strong cation resin, at a pH greater than or equal to pKa; and a second elution step with an aqueous solution of eluent having a pH greater than the pH of the first step, giving the possibility of collecting a flow enriched in the amino acid.

Method of purifying an alkali metal salt of a compound of the general Formula (I) or Formula (II)

##STR00001## wherein R.sup.1, R.sup.2 and R.sup.3 are independently H, an alkyl, an alkenyl, or a hydroxyalkyl radical containing from 1 to 18 carbon atoms, or from 1 to 6 carbon atoms; or wherein R.sup.1 and R.sup.2 form jointly together with the N atom a heterocyclic 5- or 6-membered ring; said method comprising providing a mixture comprising said, an alkali metal hydroxide and water, and subjecting the mixture to a step (X): (X) reducing the quantity of removing said alkali metal hydroxide from the mixture; wherein (A) said alkali metal hydroxide is reduced by subjecting said mixture to electrodialysis; and/or (B) said alkali metal hydroxide is reduced by adding an acid to said mixture.

Method of purifying an alkali metal salt of a compound of the general Formula (I) or Formula (II)

##STR00001## wherein R.sup.1, R.sup.2 and R.sup.3 are independently H, an alkyl, an alkenyl, or a hydroxyalkyl radical containing from 1 to 18 carbon atoms, or from 1 to 6 carbon atoms; or wherein R.sup.1 and R.sup.2 form jointly together with the N atom a heterocyclic 5- or 6-membered ring; said method comprising providing a mixture comprising said, an alkali metal hydroxide and water, and subjecting the mixture to a step (X): (X) reducing the quantity of removing said alkali metal hydroxide from the mixture; wherein (A) said alkali metal hydroxide is reduced by subjecting said mixture to electrodialysis; and/or (B) said alkali metal hydroxide is reduced by adding an acid to said mixture.

Method of purifying an alkali metal salt of a compound of the general Formula (I) or Formula (II)

##STR00001## wherein R.sup.1, R.sup.2 and R.sup.3 are independently H, an alkyl, an alkenyl, or a hydroxyalkyl radical containing from 1 to 18 carbon atoms, or from 1 to 6 carbon atoms; or wherein R.sup.1 and R.sup.2 form jointly together with the N atom a heterocyclic 5- or 6-membered ring; said method comprising providing a mixture comprising said, an alkali metal hydroxide and water, and subjecting the mixture to a step (X): (X) reducing the quantity of removing said alkali metal hydroxide from the mixture; wherein (A) said alkali metal hydroxide is reduced by subjecting said mixture to electrodialysis; and/or (B) said alkali metal hydroxide is reduced by adding an acid to said mixture.

There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) adding an ammonium salt to the mixture of alkali salts of long chain amino acid and long chain dibasic acid; (2) heating to remove ammonia; and (3) separating long chain amino acid by solid-liquid separation; and (4) acidifying the salt of long chain dibasic acid with an acid to separate long chain dibasic acid.

There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) adding an ammonium salt to the mixture of alkali salts of long chain amino acid and long chain dibasic acid; (2) heating to remove ammonia; and (3) separating long chain amino acid by solid-liquid separation; and (4) acidifying the salt of long chain dibasic acid with an acid to separate long chain dibasic acid.

The application relates to a process for drying a composition comprising an alkali metal salt of a compound of general formula (I) R.sup.1R.sup.2NCHR.sup.3COOM or formula (II) R.sup.1R.sup.2NCHR.sup.3CHR.sup.3COOM, in particular N,N-dimethyl glycinate salt, and the use thereof. In the process, the composition, in particular the N,N-di methyl glycinate salt, is dried by feeding the composition into a fluidized bed dryer and subjecting the composition to a heat treatment by contacting the composition in the fluidized bed dryer with a drying gas stream, and during the heat treatment a solution or dispersion of the composition is sprayed onto at least a portion of the composition present in the fluidized bed dryer, or alternatively or in addition the composition, in particular N,N-dimethyl glycinate salt, is fed into a fluidized bed dryer and subjected to heat treatment in the fluidized bed dryer by contacting the composition with a drying gas stream, and the temperature of the composition in the fluidized bed during the heat treatment does not exceed 50 C.